The present invention is directed generally to improved methods and apparatuses for manufacturing carpet. More specifically, the present invention is directed to the use of specific surface treatments for treating carpet backing layers to improve quality and characteristics of the finished carpet.
In the field of carpet manufacture, a stabilized backing layer is usually affixed to the carpet segment. Well known web processes exist in the carpet manufacturing field that produce a carpet backing layer that is then applied to the carpet segment. Such a backing layer is applied to the carpet segment to provide the finished carpet with needed rigidity and stability. In one known process, a molten polyolefin film or layer is applied to both sides of a rigid or semi-rigid substrate to construct a three-layer laminate backing. As the backing proceeds along the web, carpeting is supplied to the web and brought into contact with the backing. The backing is affixed to the carpet segment via heat and pressure to produce the completed carpet.
From a quality control standpoint, the backing layer must sufficiently adhere to the carpet segment for the useful life of the carpet. Trial and error in the industry has led to various practical standards in terms of the amounts, thicknesses and characteristics of the materials used for carpet backing construction. To produce the required adherence of the backing layer to the carpet, certain types of materials must be used, or else undesirable delamination may occur. In addition, the selected backing materials must have a certain thickness, density, tensile strength, etc. or risk the same backing delamination or backing separation from the carpet layer. The practical amount of backing material that must be used to achieve the required adherence of the backing layer affects the weight of the backing layer, which, in turn affects the weight of the finished overall weight of the carpet. In addition, since adherence of the backing to the carpet is dependent upon the physical characteristics of the backing material, the known workable material candidates for use in backing material manufacture have been restricted to certain preferred polyolefins. These preferred polyolefins have shown the required properties to maintain the desired carpet quality and performance. However, this fairly narrow class of preferred polyolefins, which have proven to possess the appropriate and necessary physical and chemical properties, are often relatively expensive materials that must be used in their virgin state to assure desired material performance.
Such practical constraints on backing material type have impeded the continued improvement of carpet technology, at least in terms of flexibility and variety of material selection, amount of material used, and the overall weight of the finished carpet. This, in turn, has had a direct effect on the overall production and installation cost of the finished carpet product.
The present invention is directed to an improved carpet manufacturing process enabling the use of a broader variety of backing materials, to potentially include recyclable and non-virgin materials. In addition, the present invention is directed to an improved carpet manufacturing process that can reduce the useful thickness of the backing material while maintaining the adequate backing adherence to the carpet layer and the overall carpet performance. Still further, the present invention contemplates a carpet manufacturing process that facilitates carpet installation by modifying the backing layer.
The present invention is also directed to the surface modification of composite layers used in the manufacture of carpet backing. More specifically, the present invention is directed to modifying the surface of materials used to make carpet backing by disrupting the physical or chemical nature of a material surface through the exposure of the material surface to corona discharge and/or ozone treatment.
In a still further embodiment, the present invention is related to a process for making a carpet, and carpets made thereby, comprising the steps of providing a stabilizing component to a web, with the stabilizing component having a first and a second surface. A surface modifying treatment is provided located proximate to the first surface of the stabilizing component and applied to the first surface and/or second surfaces of the stabilizing component. A material is provided to the first surface of the stabilizing component following surface treatment of the first and/or second surface of the stabilizing component. A second material is provided to the second surface of the stabilizing component and a carpet segment is provided to a web in close proximity to the second material on the stabilizing component. A surface modifying treatment is provided and applied to the second material followed by contacting and adhering the carpet to the surface-treated second material.
In addition, the present invention is directed to a carpet comprising a carpet component and a backing component. The backing component comprises a stabilizing component having first and second surfaces, with a thermoplastic material, such as, for example poly(vinyl chloride) (PVC), coating both surfaces in a total amount of from about 70 oz/yd2 to about 120 oz/yd2.
The present invention is further directed to a method for making carpet, and carpets made thereby, comprising the steps of providing a first substrate to a web, the first substrate having a first and a second surface. A surface modifying treatment process is located proximate to the first surface of the first substrate and applied to the first surface of the first substrate component. A second substrate is adhered to the first surface of the first substrate following the surface treatment of the first surface of the first substrate. A carpet component is then adhered to the second substrate after a pre-coated backing surface of the carpet component has been optionally surface-treated.
Still further, the present invention is directed to a carpet comprising a backing component having a first substrate surface that is corona plasma-treated, with the first substrate surface of the backing component in contact with a first surface of a second substrate, and a carpet component adhered to a second surface of the second substrate.
The preferred carpet backing adhesive is made from an EVA-containing material such as EVA-containing hot melt, or from materials such as styrene butadiene rubber latex, polyvinyl chloride, polypropyle, polyacetic acid, polyethylene, polyamide, polyester, natural rubber, polyvinyl butyral, etc.
As shown in
Corona discharge is an electrical phenomenon that occurs when air is exposed to a voltage potential high enough to cause ionization, thereby changing it from an electrical insulator to a conductor of electricity. The typical corona discharge equipment used to accomplish this consists of a power supply, a high voltage transformer, and a treating station that can be configured depending upon the material being processed as would be readily understood by one skilled in the field of material surface treatment. As shown in
An ozone generator was used to produce ozone that was provided to the running web. The discharged ozone bonded with the liquid thermoplastic, preferably PVC, immediately prior to applying the liquid (molten) PVC to the carpet segment. A three-dimensional corona treatment applicator was used to modify both sides of the surface structure of the stabilizing layer (fiberglass). It is believed that the same effects could be generated using an ionization bar to provide corona surface treatment application to a wide web.
There are at least two adjustable parameters for the corona treatment applicator. These parameters include the air gap between the electrode of the corona treatment applicator and the surface being treated, and the coverage of the corona arc on the material surface. Although both parameters are adjustable, each are normally treated in a pass/fail capacity after initial set-up. The corona surface application can also be measured in terms of line speed (fpm) when being applied to some materials, such as fiberglass. It is believed that the primary purpose of the corona surface treatment of material surfaces, such as, fiberglass, is to remove inherent binding agents from the surface, and to improve wet material “flow through” into the interstices of the fiberglass. It was determined that this effect improved adhesion. To insure complete surface coverage of, for example, an 82″ wide web, no less than forty-six (46) three-dimensional discharge heads may be required. Only one ionization bar would be necessary per application point if the nature of the surface treatment is so harsh as to damage the carpet face. Otherwise, the three-dimensional discharge heads for surface treatment would provide superior coverage.
The adjustable operating parameters of the ozone generation equipment include the output knob (measured in kW), the air flow knob (measured in cfm) and the sparge bar placement (measured in proximity to both the ozone application point and the ozone production unit). The tested settings for the output knob were from about 100 to about 900 kW. The tested ranges for the air flow were from about 9 cfm to about 22 cfm. The tested range for the sparge bar placement was constant at about 1 inch horizontal and about 2 inches vertical from the carpet/backing “marriage point” after the second molten polyolefin delivery station. There are multiple ways to achieve the sparge bar set-up to produce the desired level of adhesion, as would be readily understood by one skilled in the field. The position of the ozone generation equipment in proximity to the application point was also constant.
According to the present invention, the production line not only corona plasma-treats the fiberglass/thermoplastic material interface, but ozone treatment is provided to the thermoplastic/carpet interface downstream from the corona discharge treatment site. The ozone treatment provided, results from the useful placement of an ozone generator and ozone delivery system designed to introduce ozone to the thermoplastic material, preferably PVC, layer applied to one side of the fiberglass to create a “fiberglass sandwich” between the two thermoplastic material layers. As shown in
It is understood that the present invention recognizes that the corona treatment selected, as well as the location of the treatment placement on the web, is optimally selected to improve the adhesion of carpet and carpet backing layers to one another. The processes and apparatuses of the invention are contemplated and adaptable to work with layers of any state that are presented to the web (e.g. solids, liquids, gels, etc.).
The present invention therefore provides many advantages not realized before in the carpet industry. Through use of the innovative surface treatments incorporated into the carpet manufacturing web, the resulting product achieves greatly improved adherence of the carpet component to the backing layer. The backing component laminate that is produced exhibits superior quality due to the improved integrity of the bonding of the polyolefin or other thermoplastic material (e.g. PVC or PVC-containing materials, etc.) layers to the stabilizing component layer (fiberglass or polyurethane foam, etc.). This improved adherence allows far less thermoplastic material to be used in the manufacture of the backing component, resulting in a thinner backing layer that adheres to the carpet at adherence rates equal to or better than the standard, thicker conventional backing components. The thinner backing layers achieved according to the present processes, therefore result in a lighter overall finished carpet product, thus reducing shipping costs, material costs and imparting other advantages in terms of installation, and appearance, etc. In addition, the improved strikethrough and adherence of the backing component allows for the use of a broader category of backing layer candidates that includes recycled materials, such as, for example, recycled thermoplastics and other non-virginal materials, thus improving the versatility of the carpet manufacturing processes, and further reducing the overall cost of manufacturing, as more economical materials of equal performance can be used.
The present invention also contemplates optionally positioning a plasma discharge treatment unit to treat the exterior surface of a backing material to be affixed to a carpet component. Alternatively, one embodiment of the present invention is directed to surface treating the exterior of the backing component of an assembled and finished carpet with a plasma discharge. It has been discovered that disruption of the exterior surface of a backing layer of a finished carpet, preferably a polyolefin, a thermoplastic material, and most preferably a PVC-containing material, allows the carpet backing to adhere to a surface during installation to a pre-selected and desirable degree. The ability to tailor the degree of carpet adhesion to a substrate receiving a carpet during carpet installation is desirable for many reasons. An installed carpet must remain predictably stationary. However, conventional adhesives used during such carpet installation can complicate removal and repair. In addition, the extent to which a removed carpet is damaged during removal can impact the ability to recycle the removed carpet. In addition, commonly used adhesives leave a significant residue on the substrate itself, requiring additional substrate cleaning steps that delays or complicates carpet installation. The present invention therefore allows for less adhesive to be used, and potentially allows for new types of adhesive to be used, during installation. This reduction in applied adhesive during installation also results in a significant cost and time savings, and facilitates later carpet removal.
Thus, it is understood that the improved carpet manufacturing methods of the present invention yield an improved carpet product that facilitates and improves carpet installation into and onto all articles and living spaces for which carpet may be employed. That is, the present invention contemplates the installation of the improved carpeting onto flooring and wall covering in buildings, outdoor carpeting uses, enclosed and open air vehicles including, but not limited to wheeled vehicles, aircraft and watercraft, etc. All such installation “targets” herein are encompassed by the term “carpeting environments”.
A number of tests were run on finished carpet product, prepared according to embodiments of the present invention as illustrated in
The test was initiated with the sample testing allowed to run until all but about one-third of the sample is pulled apart at which point the test is terminated manually if the Instron® does not stop automatically. The upper jaw stop collar is then set at this point allowing the test to automatically complete the remaining two samples. When the machine stops or returns after pulling each sample, the “peak 2” button is pressed to obtain the highest reading. The results are shown at Table 1. The steps were repeated until each of the samples were pulled.
The results show an average increase in delamination resistance of about 23% as a result of employing the processes of the present invention.
Carpet sections were submitted for delamination testing. “Headers” were provided as samples. “Headers” are understood to be a strip of carpet cut from a roll approximately six feet by one inch. The samples for testing were cut from the header or from a tile sample to sample dimensions of 1″×6″ using a clicker press and a 1″×6″ die. The six inch dimension was in the machine direction. Three samples were taken from the #1 tile side (the “right”), three samples were taken from the center of the header and three samples taken from the #4 tile side of the header (the “left”). The action back and urethane layers were attempted to be separated from the primary back by physically pulling the layers apart using an Instron® destructive testing machine. If during the tearing procedure, the foam, but not the primary backing separates, the delam test is considered “good”. The minimum accepatable value for separation force applied (e.g. peel strength) is 3.0 lbs as recorded on the Instron, according to ASTM D-3936. Test results showing separation when force below 3.0 lbs. is applied is considered failing. Test results between 3 and 5 lbs. are considered questionable. Test results above 5.0 lbs. Are considered “good”. According to the present invention, the backing is preferably adhered to the carpet at a peel strength of from about 3 lbs. to about 25 lbs. depending upon the desired finished properties of the carpet product, more preferably from about 5.0 lbs. to about 25 lbs.
For urethane action back carpet tiles, a delamination test was considered “good” if the urethane foam tears and there was no separation of the primary and secondary back at the adhesive layer. Easy separation of the primary and secondary backs or gummy adhesive at the separation were indications of questionable or failing lamination.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
This application is a continuation in part application of U.S. patent application Ser. No. 11/124,991, filed May 9, 2005, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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Parent | 11124991 | May 2005 | US |
Child | 11456124 | US |